FR2560684A1 - METHOD AND DEVICE FOR DETECTING TOXIC GASES - Google Patents

Abstract

THE PORTABLE DEVICE FOR IDENTIFYING A HAZARDOUS COMPONENT IN AIR OR ANOTHER GAS, ACCORDING TO THE INVENTION, INCLUDES A NETWORK OF SMALL DETECTORS51 WHICH ARE EXPOSED TO GAS TO GENERATE A COMBINATION OF RESPONSE SIGNALS, THIS IS COMPARED TO COMBINATIONS OF REFERENCE RESPONSE SIGNALS USING A MICROPROCESSOR56 TO IDENTIFY THE COMPONENT OR ITS DERIVATIVE WHOSE NAME IS DISPLAYED ON A SCREEN60. THE NUMBER OF RESPONSE SIGNALS CAN BE VARIED BEYOND THE NUMBER OF DETECTORS BY VARIING THE OPERATING VOLTAGE, TEMPERATURE OR OTHER CONDITION ASSOCIATED WITH ONE OR MORE DETECTORS TO OBTAIN A SET OF RESPONSE SIGNALS FROM ONE OR MORE DETECTORS. SEVERAL DETECTORS. IN AN EXAMPLE OF AN IMPLEMENTATION, THIS DEVICE CAN IDENTIFY UP TO 50-100 HAZARDOUS COMPONENTS.

Description

Method and device for detecting toxic gases The present invention

  relates to analytical devices and more particularly devices for detecting the presence of at least one polluting product

  or other hazardous component in a large sample

  zeux. The invention further relates to a device in

  which a set of electrical response signals se-

  are supplied by a set of detectors, these

  response signals constituting a characteristic combination

  of a dangerous component. More specifically, the invention relates to a portable instrument which can be

  used at field locations for detection

  tion and identification of at least one danger-

  in a gas by means of a comparison of the

  response signals from detectors to one or more stored reference combinations

in an instrument memory.

  With particular regard to the use

  at locations on the ground for chi-

  widespread and the equivalent, we generally have

  associated with devices intended to detect the presence of a polluting product or of another dangerous component in a gas with a particular selected compound. Of

  selective detection devices for hydrogen sul-

  furry, carbon monoxide, ammonia, and the like

  analogous substance can be considered to represent

  sensitive. Essentially, these devices measure one or a few selected pollutants and are not designed to identify the hairy product. When a gas to be analyzed can contain a non polluting product

  known, it is generally necessary to obtain a

  tillon the gas and send it to a laboratory for e-

  perform a remote analysis. The time necessary for the transmission of the sample and its analysis generally delays by a significant time a significant identification of all the harmful components and / or their

concentration in the gas.

  Semi-portable versions of the analyzers

  gas or infrared chromatography of the

  The most powerful boratory drugs have been introduced commercially in recent years. In addition to being rather heavy, bulky, unwieldy and expensive, these

  instruments have certain inherent limitations.

  Gas chromatography devices cannot operate

  operating in a real-time continuous monitoring mode.

  Infrared ray analyzers require a

  delicate optical positive with a rather long absorption path, which contributes to their volume, their weight and their lack of maneuverability. These instruments should

  generally be ordered and their results interpreted

  ted only by well-trained professionals.

  An object of the invention is to provide a device

  tif for the detection and identification of one or more

  several dangerous components of a gas.

  A second object of the invention is to provide a device capable of identifying a dangerous component

  in a gas from the combination of feedback signals

response to a set of detectors.

  A third object of the invention is to provide a device for identifying one of a number of

  unknown hazardous components in a gas.

  Another object of the invention is to provide a

  device that can provide a variety of combinations of

  response signals and can thus identify a set of

  ble of possible hazardous components in a gas.

  A further object of the invention is to provide

  provide a device capable of analyzing a gas

on the spot.

  Another object of the invention is to provide a portable device which can be easily transported to locations on the ground and controlled and

  used by unqualified or semi-qualified personnel.

  These and other goals will become apparent from the

detailed description which follows.

  In summary, the invention relates to an analytical device intended to identify at least one dangerous component in a gas such as air by the use

  a network of small detectors, preferably all

  breasts, such as existing electrochemical, semiconductor, noble metal heated catalysts,

  or photoionization. We realized that the com-

  pairing of response signals from these detectors

  teurs provided the identification of the component when

  it was compared to a combination of feedback signals

  reference answer that can be established for the compound

  health in the device memory. In the device,

  at least two of the detectors produce electrical signals

  different response triques from interaction

  chemical of the component or its derivative with each detection

  tor. The network also preferably includes at least one heating filament capable of producing one or more

  several derivatives by oxidation or by pyrolysis of the

  posing. In addition, the response signals of the detectors can be varied by variations of one or more of the operating conditions such as voltage, temperature, sample flow, or deviation of the sample passage through a selective chemical filter, and the like, so the number of different response signals is

  greater than the number of detectors and the number of components

  health in the gas. This increase in the number of si-

  Different response methods improve the selectivity of the device with regard to the identification of dangerous components.

  The device is particularly useful as a pe-

  tit portable instrument suitable for use

  in the field to identify one or more hazardous components of a spilled chemical material or

  in another critical circumstance. A means of pro-

  grammage is provided to constitute a combination of response signals from the detector network and to compare the combination of response signals formed with one or more combinations of reference response signals stored in a memory

  the instrument. In an exemplary embodiment, the provision

  sitif includes two different heating filaments and four different electrochemical detectors with a programming means allowing to change at least

  an operating condition for the four detectors

  electrochemical sensors to identify any-

  which of a set of 50-100 hazardous components. In addition, analysis of the response signals also provides

  data on the concentration levels of the compound

  or hazardous components. All these functions

  are incorporated in the instrument and are preprogram-

  so that they can be performed by a person

  generally unqualified personnel. In general, the instru-

  has a power requirement of less than about 2 watts and the detectors are arranged in a space

  less than about 8 cm by 15 cm by 8 cm.

  The device also has the ability to control

  continuously levels of a substance in

  and trigger an alarm when a pre-

determined is reached.

  Other features and advantages of the pre-

  sente invention will be highlighted in the descrip-

  tion following, given by way of non-limiting example, with reference to the accompanying drawings in which: Fig.lA, lB is a series of diagrams representing

  combinations of response signals for acryloni-

  trile from a network of detectors including four electrochemical detectors; Figure 2 is a series of diagrams representing the combinations of response signals for pyridine

  from a network of detectors including four detectors

  electrochemical tectors; Figure 3 is a pair of signal histograms

  response channels of 16 channels for toxic vapors

  acrylonitrile and pyridine; Figure 4 is a pair of diagrams representing

  the proportionality of the response signals in the

  most intense values in Figure 3 as a function of the toxic vapor concentration sampled; Figure 5 is a schematic representation of an embodiment of the invention with a network of

  detectors including sample chambers

  nected in series; Figure 6 is a schematic representation of a

  second embodiment of the invention with a

  detector bucket with parallel connected sample chambers; Figure 7A, 7B shows a top view of a portable instrument implementing the invention; and Figure 8 is a schematic representation of

  data generation and processing systems as-

associated with the invention.

  The invention relates to a method and an associated device for identifying at least one hazardous component in a gas. The invention is particularly important for use in the field as

  portable instrument for detecting one or more components

  dangerous health in the air from a chemical material

  than widespread, from a fire, or other form of pollution.

  Representative hazardous components for which

  the invention provides useful results include acrylic

  lonitrile, ammonia, benzene, carbohydrate

  ne, carbon tetrachloride, chlorine, chlorofor-

  me, cyclohexane, ethyl acrylate, formaldehyde, hydrogen sulfide, nitric oxide, nitrogen dioxide, nitromethane, pyridine, sulfur dioxide, sulfuryl fluoride, tetrahydrofuran, toluene

and vinyl acetate.

  The toxic levels (time-weighted average) of the above hazardous components vary by approximately 1 ppm (millionth) for chlorine or the form

  about 300 ppm maldehyde for cyclohexane. However

  However, for short term exposure, it may be

  more important to detect and identify one or more

  of these components at levels of the order of 2

  at around 400 ppm (usually 10 to 50). In the-

  These components are detected by their interaction.

  chemical or that of their derivatives with detectors

  network tutors. Generally, the component has a chemically active group or groups or it can be oxidized or reduced to form one or more derivatives comprising an active group or groups such as carbon protoxide, nitrogen dioxide, etc.

  In the invention, each of the detectors of a

  bucket is provided with a housing or other device containing the gas forming a sample chamber, the combination constituting a detection means. Means are provided for introducing a gas sample into the detection means, which can typically be the electrode.

  detection of an electrochemical gas detector,

  especially an ammeter gas detector. Of the-

  tectors include at least two and preferably at least 3-4 detectors generating different electrical response signals for a component or its derivative for

  provide a different set of response signals. Ge-

  generally the response signals differ between

  detectors for the same component and between different

  components for the same detector.

  As an example of how an instrument works

  implementing the invention, the instrument can be adjusted

  so that it performs one of two main functions, control or identification. During a check for the presence of an unknown air contamination product, the detector network is connected directly to a sampling probe, and a signal from one of the: detectors indicates the presence of a component possibly dangerous near the entrance of the probe. To identify the detected component, a sample is first extracted from the probe inlet to be placed in a 1 liter sampling bag (L). The collected sample is then drawn into

  the detector network at a speed of around 0.01-

  0.1 L per minute, and detectors are switched to four differently selective modes at intervals of

  appropriate times (usually 40 seconds / interval).

  The response signals of each detector at the end of each interval are recorded in one of 16 independent data channels, and the relative quantities of

  these response signals provide the necessary information

  necessary to identify the particular component giving

  giving birth to the signals observed. The mid-controller

  croprocessor identifies a compound based on the data

  recorded data and then it adjusts the network of

  maximum sensitivity for this compound in the control mode. The number of detectors and the time required can be changed depending on the complexity of the

  product analyzed. Simpler mixtures may arise.

  stop smaller networks and fewer modes of

  more complex than the products analyzed.

  You can also set the alarm to match

  lies at an appropriate level, associated with the exposure limit

  short-term (STEL) or immediate life and health hazard (IDLH) concentration of the identified compound. The detector network can consist of

  electrochemical, catalytic or seismic type detectors

  conductors, or combinations of these and other types

  very types of low portable gas detectors

  power, and which are preferably mainly electric

  trochemicals. The detector array may also include one or more heating filaments having exposed catalytic surfaces. Suitable types of electrochemical detectors include amperometric detectors having sensing electrodes

  in gold or platinum supported by an exchangeable membrane

  ion ion, for example polyfluorosulfonic acid, which also serves as a detector electrolyte, or by a porous polytetrafluoroethylene membrane, permeable to gas and impermeable to the electrolyte, the detector electrolyte being a strong acid, such than H2S04 or H3P04,

  or a strong base, such as KOH, in aqueous solution.

  It is also possible to use detectors comprising other metallic and non-metallic electrodes in

  aqueous or non-aqueous solutions. The network can also

  one or more heating filaments

  ge containing a catalytic material, such as platinum,

  palladium, iridium, rhodium or gold, and pre-

  two separate filaments, for example one from

  tine and one of rhodium. These filaments can function to provide different degrees of oxidation of the component and also to serve as detectors whose current

  electric varies according to the concentration of the

posing.

  Another way or a complementary way of increasing

  tell the number of operating modes differently

  selective, and thus to obtain an improved selectivity

  rée, consists in deviating the sample to make it pass-

  be in one or more selective chemical filters (for example, cartridges containing substances with a strong chemical affinity for certain compounds)

  by means of solenoid valves controlled electronically-

  ment (not shown). These filters can include activated carbon or other absorbent substances to suppress organic vapors or chemical reagents such as triethanolamine on a support

  to remove nitrogen dioxide. By comparing the if-

  Detector network response signals for an exchange

  not having passed through a chemical filter at the

  response signals for the same sample having passed through

  one or more different chemical filters, the identi-

  fication of the compound or compounds tested can be

greatly facilitated.

  As an example of the detection of components in

  gereux, Figures 1 and 2 respectively provide data for acrylonitrile and pyridine. The

  network includes four electro- toxic gas detectors

  different chemicals, two of which have electrodes

  of detection meshed in pure gold buried in a mem-

  polyfluorosulfonic acid ion exchange brane, one of the electrodes being maintained at a potential of 1.0 volts and one at a potential of 1.4 volts relative to the reversible hydrogen electrode (RHE), one having a similar electrode made of a platinum mesh

  platinized and maintained at 1.3 volts relative to the elect

  RHE trode and one comprising a detection electrode

  of platinum black welded to a tetrafluoro membrane

  porous ethylene, immersed in an electrolyte of sulfuric acid in an amount of about 25-30% by weight, and

  setting to a potential of 1.1 volts compared to the elect

  RHE trode, and the network includes two heated noble metal filaments, one of platinum and one of rhodium, which work to oxidize or partially oxidize many of the compounds in the air. The four detectors can be quickly switched to one

  of the following four operating modes: (a) the

  platinum lament heated to about 850 C; (b) the fila-

  rhodium ment heated to about 900 C; (c) the rhodium filament heated to about 1000 C; and (d) the two filaments out of circuit. In this arrangement, four modes and four detectors provide a total of 16 independent data channels as shown in

  Figures 1 and 3. In Figure 1 (Figure lA and Figu-

  re 1B), each of the four detectors was exposed to predetermined amounts of acrylonitrile in the air and operated in each of the previous four modes. As the data indicate, each detector

  has a different electrical response configuration or model

  ferent for exposure to acrylonitrile, the response varying depending on the concentration. A result

  similar is shown in Figure 2 for pyridi-

  born. The responses in Figures 1 and 2, when normalized in accordance with Figure 3, present different histogram models for different

  compounds, which makes it possible to identify an exchanging compound

  streaked. In addition, as shown in Figure 4, the large

  the strongest channels of the Fi-

  gure 3 can be used as an indication of the concentration

  of the identified hazardous component.

  Again compared to Figure 4, the data also indicate the time-weighted average threshold exposure level (TWA) and the concentrations

STEL or IDLH of the two components.

  The device can operate either to control

  ler the level of a component, ie to identify unknown components. Figure 3 shows that channel 6 provides the strongest signal for acrylonitrile, while channel 7 provides the strongest signal for pyridine. Therefore, the detector network as a controller is tuned relative to channel 6 after identifying acrylonitrile or relative

  at channel 7 after identifying the pyridine.

  A programming means is provided for trans-

  forming detector responses into a combination of response signals. As shown in Figure 3, responses can be positive, zero or roughly

  zero, or negative. These responses constitute a collection

  one or more combinations of feedback signals

  which are used to identify the component.

  Advantageously, the programming means include

  takes a means to compare the combination of response signals formed with one or more reference combinations which are each characteristic of a particular component or of a type of component. Preferably, the programming means also comprises a memory

  which provides the reference combinations for the comparison

right.

  Before the comparison operation, the first

  combination or initial combination of response is conver-

  tie in a second combination in which are deleted

  even noise and space readings. As an example, the responses of Figure 3 are obtained by dividing the responses initially obtained by the corresponding concentration of toxic gas and also by the noise

  means of each detector corresponding to a given channel.

  The values in each channel are then normalized by dividing them by the highest response in the combination of 16 channel responses for the result

shown in Figure 3.

  To identify an unknown compound in a sample

  tillon of gas, the programming means can first reject the possible compounds whose response combinations require significant signals in the channels

  o the sample tested does not give a significant response

  cative. In the examples of Figures 1-3, a non-significant response in Channel 1 (corresponding to the

  Detector n 1 in Operating mode n l) per-

  excludes pyridine as a possible compound (see Figure 3b), but it is compatible with the presence

  acrylonitrile (Figure 3a). The means of programming

  tion can then select the remaining possible compounds whose response combinations show strong or intense responses in the same channels

  that in the combination of responses actually observed

  vee. For example, intense responses in Channels 5, 6 and 7 in Figure 3 designate acrylonitrile as the possible compound considered. Finally, if this selection operation gives more than one probably possible compound, the concentrations of each of these probably possible compounds can then

  be estimated by solving several algebraic equations

* simultaneous (deduced from an analysis of the combination

  reference response sound) based on a comparison

  of the combination of effective responses to the combinations

  response sounds of compounds likely to be

  wheat. All of these comparisons can be made quickly using a microprocessor mounted in

the instrument.

  Figures 5 and 6 are diagrammatic representations

  detector array layouts. As shown in Figure 5, the sample inlet 10 includes a pump 12 to ensure passage of a sample

  up to filaments 13 and 14 which can be laid

  either on or off or both on and off during analysis. A filter 15 is provided to remove the particles. The resulting sample can be the initial component or its derivative or its derivatives depending on whether filaments 13 and / are used.

  or 14. The resulting sample is then sent se-

  essentially detectors 16, 17, 18 and 19. These detectors are also arranged so that the very first detectors in the series interact with only minimal amounts of the sample

  without significantly changing the intro concentration

  pick in the sample chambers of the following detectors. In Figure 6, the sample is sent to filaments 40 and 41 and then to detectors

  42, 43, 44 and 45 arranged in parallel. After an inter-

  action with these detectors, the sample is removed by

  a pump 46. Data entry and po-

  tentiostat are designed to receive the feedback signals

  response and to produce variations in detector voltages. Figure 7A and 7B shows an arrangement of a portable instrument in side and front views. As shown, a housing 50 is provided which may be about 8 cm by 28 cm by 22 cm. Of

  electrochemical cells 51 and a filament 52 are pre-

  seen as a network. A pump 53 is used to introduce the sample

  furrow. Batteries 54 provide a power

  table. A filter 55 is used to remove the particles. Four circuit boards are provided. A wafer 56 is that of the central processing unit (CPU), a wafer 57 is that of the potentiometer and self-control circuits, a wafer 58 is that of the analog circuit, and a wafer 59 is that of the circuits d 'power, alarm and display. A display module 60 provides data display

resulting from each test.

  Figure 8 shows the interconnection of the

  parts of the device. Electrochemical cells 70 are controlled by potentiostats 71, the signals of

  response from cells 70 being sent to a circ

  cooked analog input / output 72 which also receives

  data and / or instructions from an oxygen detector

  gene 73, alarm 74, inflamed gas detector

  mable 75, a battery controller 76, a filament control circuit 77, and a central processing unit CPU 78. A digital input-output circuit 79 is also operated by a register of switching 80, the filament control circuit 77, the CPU 78, and a pump control circuit

  81. Visual and alarm signals are provided.

  nis by the digital input-output circuit 79.

  The device is provided with a microprocessor programming means in which a main program

  is used to select any of a

  seems to be functional programs that can in turn use one or more of some of the other pro-

  functional grams and one or more useful programs

  shut up. The selection of the functional program in

  the preferred embodiment is milked by the use of

  tion of an appropriate button located at the front of the box-

  is lying. A display is provided to indicate the name of the component identified by the programming means

  in the test or component that is checked.

  In a preferred embodiment, the pro-

  functional grams are called the Ident mode, the mode

  Select, Universal mode, Zero mode, Standard mode-

  swimming, and Test mode. All these programs are executed by keys used by the individual operators which activate the microprocessor to run the desired program. As examples of these modes, those of the following description are provided in which the term

  "gas" is used to refer to the "component" that is detected.

  Ident mode collects a group of

  data on an unknown gas (16 data points, 4 cel-

  electrochemical cells in 4 modes), to subtract a group of null data (the signals obtained from

  basic air), multiply by the metering data

  lonnage (obtained from a calibration gas for

  take into account the variable performance of cells

  them if necessary), and by treating the result as a vector with 16 coordinates, it makes it possible to compare the

  data to a series of combination data groups

  its stored in a library for different gases (the unknown gas data is normalized, and a Euclidean distance calculation is performed between it and each combination group). The gas with the data

  closest to the unknown combination is selected

  mentioned as the appropriate gas identification for the gas, and all combination data groups having an unknown gas distance of two or less

  times the minimum distance are selected as iden-

  possible or incipient tifications. The gas concentration is calculated by multiplying the data from

  of the most intense channel by a coefficient of concentration

  tion stored in the combi data library

  naison, and, from the results of this calculation, the IDLH level in percentage is also determined. All this information is displayed, and alarms are triggered for an IDLH level of 25% and 1OO%

  (by means of a beeper and LEDs

  minescent LED flashes for 25% or more, and by means of a permanent vibrator or light-emitting diodes

  LED for 100% or more). Finally, the operator has the pos-

  ability to review information (identified gas,

  centration, IDLH percentage, number of missing identities

  incipient tifications, and a list of absences from iti-

  incipient dentifications) or to rewind the program-

  main or a "Main" routine by pressing the appropriate key. The program replay

  Main stops all alarms.

  Select mode allows operator to choose

  which of the gases contained in the combi-

  reasons must be checked. The gas is chosen by moving forward and backward through the library,

  using the keyboard (only the name of the gas is displayed

  read). When the proper gas is located, the operator

  can choose either to trigger the mode or to redefine

  roll the Main program. Once triggered, the device is only put into operation in the most sensitive mode, so that there are only four data channels taken. The Euclidean distance is calculated based on the four channels only to obtain a measure of how well the measured gas fits the combination vector. This feature is used to warn of the presence of vapor mixtures or

  incorrect designation of chemicals. The Se mode

  lect provides a measurement in a time interval ap-

  property for mode (32 to 50 seconds). The program

  can be interrupted after any cycle.

  Universal mode consists of detecting components

  possibly dangerous before their identification.

  A Pt or Rh filament works and is stopped from

  cyclically with cycles of use of 5-20 se-

  condes. Detector response signals are indi-

  ques to the operator in the form of a group of four nom-

  arbitrary beres; the alarm is triggered when a

  overall cell output exceeds a predetermined threshold.

  The no signal state of the device should be measured frequently. When entering mode

  Zero, the 16 information channels are entered in use

  sant the same program (Volts) as that addressed by the

  Ident mode. Then the 16-element vector is trans-

  féré up to a special register. In subsequent measurements, this value is subtracted from all

  input data in Ident, Select or Uni modes

versel.

  Likewise, it is expected that aging-

  electrochemical cells and filaments

  traline progressive variations of the re-

  response over time. Calibration mode is designed to calculate a correction factor for each channel. A sample of a calibration gas such as dioxide

  sulfur is linked to the device. The sai- subroutine

  data set (Volts) is addressed. The resulting vector is compared with that stored in the library.

  combinations, and the report is stored in a log

  be special. Each measurement made later in Ident or Select modes is corrected by this report. If Calibration mode is not selected, a vector of

  fault is loaded into the calibration register,

  Ci representing the state of the cells at the time when

  compiled the library.

  Test mode gives access to the same control program that was used in the development

  programs on the device. The con-

  trôle enables the following functions to be performed:

  (a) reading any part of me

  moire, (b) the change of values in the RAM

(RAM),

  (c) resetting the instrument, and

  (d) the addressing of certain subroutines used

  for checking the device. For example, you can use a Control to manually adjust the pumping speed and

the two filaments.

  Test mode is not used for operator use of a routine. If entering test mode inadvertently, two keys are used to

exit from this mode.

  As established in the explanation above, the invention provides a useful analytical device on

  the field to perform the three detection functions

  tion, identification and measurement of a component in a gas. Advantageously, the device is portable and it includes a microprocessor programming means

  thanks to which multiple functions can be performed

  compared to a gas component and the results can be shown on a device display screen.

  The foregoing description of the invention has been

  made for the purpose of illustration, without being exhaustive or limiting the invention to the precise form explained. It is obvious that many modifications and changes can be made 18 without departing from the scope of the invention as defined.

  in the claims which follow.

Claims (10)

  1. Instrument to identify at least one component   dangerous in a gas sample, including:   a detection means including a detection network   tectors (13,14,16 to 19; 40,41,42 to 45; 51,52; 70) of which at least two of the detectors (16 to 19; 42 to 45; 51; 70) generate electrical signals of different response depending on the chemical interaction of the component or its derivative with each of the two detectors; means (10,12; 53) for introducing the sample into the detection means;   means (47; 57.58; 71.72) for forming a combination   generation of response signals from the detection means exposed to the sample; means (47; 56; 78) for providing a set of combinations of reference response signals including   a combination of reference response signals serve   to identify the component; and means ((47; 56; 78) for comparing the combination of response signals formed with at least one combination of reference response signals to identify the component.   2. Instrument according to claim 1, character-   rised in that the network includes at least one heating filament (13, 14; 40,41; 52) in addition to the two detectors   (16 to 19; 42 to 45; 51; 70), the heating filament per-   putting to form at least one derivative of the component.   3. Instrument according to claim 1, character-   that the detection means comprises means (47; 57; 71) for changing a functional condition of the gas sample or of at least one of the two detectors   to thus vary the detector response signal   said change means enabling one or more   multiple detectors to generate more than one signal   response and the number of response signals for the network   of detectors being greater than the number of detectors.   4. Instrument according to claim 3, character-   laughed at in that the means of comparison (47; 56; 78) includes   takes a means to compare at least one signal of re-   non-significant response of a detector in one of the con-   functional editions to at least one combination of reference response signals having a significant response configuration for the detector in the same   functional condition, and in that the means of change-   ment comprises means for diverting the sample to pass it through a chemically selective filter (15;).   5. Instrument according to claim 1, character-   laughed at in that it comprises a programming means (47;   56; 78) to selectively identify an unsuitable component   bare or to control the concentration of a known component of the gas, this programming means comprising a   means for mathematically modifying the feedback signals   response taking into account the detector calibration and background noise.   6. Instrument according to claim 1, character-   laughed at in that it comprises a transport case (50) including an electrical supply means (54), the   network of detectors (51,52), the means (57,58) for training   sea the combination of response signals the means to   memory (5), and the comparison means (56).   7. Instrument according to claim 1, character-   that the detectors include a set of electrochemical detectors (16-19; 42-45; 51; 70) or   at least one semiconductor detector.   8. Instrument according to claim 1, character-   laughed at in that it comprises at least one filament of heating   fage (13,14; 40,41; 52) placed upstream of the detection network   teurs (16-19; 42-45; 51), and in that, in the network, the detectors having the highest response signals   are placed downstream of the other detectors.   9. Instrument according to claim 1, character-   laughed at in that the training medium (58; 78) includes   a means to convert a first combination of if-   response signals in a second combination of response signals before the comparison of combinations is carried out. 10. Method for identifying at least one component   in a gas sample, characterized in that it contains is:   introduce the sample into a detection network   agents for exposing each of the detectors to the component or to at least one of its derivatives;   the network including at least two detectors   generating electrical signals of different response depending on the chemical interaction of the component or its derivative with each of the two detectors; forming a combination of response signals from the response signals of the detectors; and compare the combination of response signals formed to at least one combination of response signals   to identify the component.